Mapping and measuring the troposphere pollutants originated from the 1997 forest fire in south east asia
Mazlan Hashim, Kasturi Devi Kanniah, Abdul Wahid Rasib and Lim Chee Ming
Department of Remote Sensing
Faculty of Geoinformation Science and Engineering
Universiti Teknologi Malaysia
81310 Skudai, Johor, Malaysia.
Keywords: remote sensing, AVHRR, forest fire, aerosols, gases, atmospheric pollutants.
Abstract:
The massive forest fire in Indonesia in 1997 affected the whole Asian region by transporting large quantity of smoke plume with Malaysia bearing the brunt due to being nearer, wind direction and weather conditions. In this study, AVHRR (Advanced Very High Resolution Radiometer) satellite data were used to detect and subsequently map the five primary sources of fire pollutants namely Carbon monoxide (CM), Sulphur dioxide (SO
2), Nitrogen dioxide (NO
2), Ozone (O
3) and particulate matter less than 10 micron ((PM10) in Peninsular Malaysia. A multi regression analysis was used in this study to establish a statistical relationship between atmospheric pollutants (ppm) readings recorded at 5 stations around the Peninsular and reflectance values from AVHRR data. This model, based on 5 samples was then applied to all the pixels in the image covering the whole Peninsular Malaysia. The obtained values are in parts per million (ppm) for all the constituents except for PM10 in ug/cu.m.
1. Introduction
In Southeast Asia, currently it has become evident by estimates from satellite remote sensing data that biomass burning play an important role in air pollution and atmospheric chemistry. Palm oil plantations in Riau and other Sumatera provinces are the main source of the fires as many companies use fire as a cheap method to clear the land for the next planting season (UNEP, 1999). Combustion products of biomass burning include various hazardous gases such as carbon dioxide, carbon monoxide, nitrous oxide, oxides of sulphur, methane, non-methane hydrocarbons, nitric oxide and various types of atmospheric particulates.
Gases and aerosols are very efficient at scattering sunlight. Scattering of solar radiation by aerosols can limit human visibility in the troposphere; this is the phenomenon known as haze. Some aerosols, especially black carbon particles created by fires, efficiently absorb sunlight and results in heating of the atmospheric layer, whilst, scattering properties cause a redistribution of radiation including losses back to space. In the lower atmosphere, aerosols and gases can modify the size of cloud particles which changes how the clouds both reflect and absorb sunlight thus, modifies the radiative budget. The 1997 and also the subsequent fire scenarios (1998, 1999 and Mac 2000) have affected the whole Asian regions with Malaysia bearing the brunt due to being nearer to Sumatera, wind directions (Monsoon Seasons) and weather conditions. In Malaysia, the main pollutant that is contributing to the haze is PM10, besides CM, SO
2, NO
2 and O
3 (Vadivale 1997). Pollutants from forest fire can be hazardous to the environment and human health.
The ability to detect the extent and amount of the forest smoke plume during early stages of the disaster would greatly assist in the emergency response planning by responsible teams. Many studies have been conducted using remote sensing technique to map or measure the forest fire constituents (Kaufmann et al (1990), Cahoon Jr. et al (1994) and etc. used AVHRR data to estimate the particulates and trace gases originated from forest fire in Brazil, China and South America respectively. Satellite remote sensing can determine the distribution and total content of the pollutants over large areas. Coarse spatial and high temporal resolutions of AVHRR sensor onboard NOAA (National Oceanic and Atmospheric Administration) satellites made it possible to detect and monitor the fast spread of fire emissions over countries, regions or even continents continuously.
In this study NOAA AVHRR data were used to map and measure the spatial distribution of PM10, CO
3, NO
2, O
3, and SO
2 on 17, 28 and 29 of September, 1997 (period of thick haze episode) over Peninsular Malaysia. The current study is an extension of previous work that looked at the determination of haze in API (Air Pollution Index) units (Asmala, 1997).
2. Data and Technique
Channels 1 and 2 of AVHRR (short wavelength; 0.58- 1.10
mm) were selected to be used in the extraction of fire emission constituents information. Atmospheric molecules and other tiny particles that are much smaller in diameter than the wavelength of the interacting radiation are efficiently diffuse the radiation. The effect of Rayleigh scatter is inversely proportional to the forth power of wavelength and therefore there is much stronger tendency for short wavelengths to be scattered by this scattering mechanism than long wavelengths (Lillesand and Kiefer 1994). Hence, the contribution of measured radiance at the top of the atmosphere from the path radiance is larger for shorter wavelengths. Smoke originated from wild forest fire is not observable in the mid IR (2.2
mm) due to the large ratio of wavelength to the size of the particles. Kaufman (1993) also used sun photometer/ radiometer in the 0.44-1.03
mm range to make measurements of the path radiance and the aerosol optical thickness from the ground.
| |
Monitoring stations |
Geographical location |
| |
|
Longitude |
Latitude |
| A |
Kuala Lumpur |
101°42.274'E |
0.3°08.286'N |
| B |
Prai |
100°24.194'E |
05°23.890'N |
| C |
Pasir Gudang |
103°53.637'E |
01°28.225'N |
| D |
Bukit Rambai |
102°10.554'E |
02°15.924'N |
| E |
Bukit Kuang |
103°25.826'E |
03°16.260'N |
Figure 1. Location of the 5 atmospheric constituents monitoring stations (shown by letters A, B, C, D and E).and their corresponding geographical locations. Fire emission constituents (ppm level) data were provided by Alam Sekitar Malaysia Berhad (ASMA).
(Source: Ahmad and Hashim, 1999).
